December 12, 1895] 



NATURE 



127 



while thatching is a rural fine-art handed down mostly 

 from father to son. So it is probable that the corn-rick 

 in Norton farmyard (p. 54) is similar in make and shape 

 to that, for instance, under the thatch of which " were 

 assembled near an hundred" harvest mice; although 

 most probably in White's time all the ricks were erected 

 on " staddles." The rick in the illustration is unlike the 

 oblong square ones usual in some districts, and the round 

 ones prevailing in others ; it is square, and has the comers 

 neatly rounded. There are some excellent views of the 

 irregularly shaped thatched cottages, which are probably 

 but little altered, and possibly the same may be said of 

 the substantially-built houses seen when looking across 

 the Plestor. The Plestor, the famous wooded " Hanger," 

 and the Long Lythe — a favourite walk of White's — 

 are quite familiar scenes in the mind's eye of White's 

 readers. Views of Wolmer Pond and Wolmer Forest, 

 once the haunt of wild red deer and black game, and 

 where White found teal breeding, which he looked upon 

 as "a great stroke in natural history," are very suitable 

 illustrations, and we are charmed to have a picture of 

 one of the " little round ponds " on the sheep-downs, 

 which never dried up. But why insert a view of 

 Stonehenge ? White certainly mentions it ; but so he 

 does Oxford, Calabria, and other places which have 

 nothing particular to do with Selborne. The figure of 

 the " Rook-starver " (Rook-scarer) suggests the question 

 whether this was a name of White's day. . Most of these 

 curious local names are old ; but the Hampshire villagers 

 must have differed from those of the Midlands, for 

 instance, who invariably call rooks crows, and talk about 

 " Crow-keeping." One of the prettiest views is that of 

 an old cottage in the Lythe backed with clumps of hang- 

 ing wood, and there is a very nice picture of a rookery. 



There are a good many illustrations of birds, which in 

 some, if not all, cases seem to have been reproduced 

 from photographs of stuffed specimens. With hardly an 

 exception they are quite as unsatisfactory as illustrations 

 of this kind usually are, and some of them are exception- 

 ally bad. 



In the present edition the arrangement of the letters 

 to Pennant and Daines Harrington in two separately 

 numbered series is departed from, the whole being fused 

 and arranged chronologically ; this, especially to those 

 used to the other style, makes the want of an index more 

 felt. The second volume concludes with the new letters 

 to members of the Barker family, and the Calendar. 



O. V. Aplin. 



PLANT PHYSIOLOGY. 

 Das PJianzenphysiologische Prakticum. Von Dr. W; 

 Detmer. Mit 184 abbildungen, zweite vollig neu 

 bearbeitete Auflage. (Jena : Fischer, 1895.) 



IN the new edition of this standard book, the general 

 arrangement of the first edition has been for the 

 most part adhered to, but in other respects great changes 

 have been made. Nearly every section has been re- 

 written and enlarged, a large number of new experiments 

 have been added, and in every case great care has been 

 taken to give full details for carrying out the observ- 

 ations described. Among the sections added, the follow- 

 ing may be mentioned : on the relation of the stomata to 

 NO. 1363. VOL. 53] 



assimilation ; an account of experiments on species of 

 the natural family Papilionacefc, illustrating their re- 

 lation to the bacteria normally found in their roots ; on 

 nitrification, including an experiment on nitromonas, 

 one of the remarkable organisms capable, without the 

 action of light, of forming organic substances from 

 inorganic materials. Another addition is the section 

 on mykorhiza. In dealing with the intercellular system 

 of plants, it is strange that Prof. Detmer still quotes 

 the intercelliflar space, which accompanies the bundles 

 of Zea Mays, as an example of a passage which is 

 of importance in the exchange of gases and the 

 aeration of the tissues ; while it is almost certain that 

 this passage is chiefly serviceable in conducting water in 

 the plant. The sections dealing with transpiration have 

 been materially enlarged and improved, although it is 

 difficult to see how the author could be inclined towards 

 Westermaiers and Godlewski's theories after Strasburger 

 had so completely answered them. It is to be noted thaty 

 in an appendix, Prof. Detmer appears to accept the 

 theory which regards the upward motion of the sap as 

 due to the tension set up by the evaporation taking place 

 in the leaves, and transmitted downwards through the 

 water-columns in the tracheidal system. He, however,, 

 apparently by an oversight, attributes this theory to Prof. 

 Askenasy, who himself, in the paper describing the 

 theory, acknowledges the priority of its English authors. 



In treating of the development of heat and phosphor- 

 escence by plants, much new matter has been added. 

 The raising of the temperature of flowers above that of 

 their surroundings, is doubtless often an attraction for 

 their insect visitors ; and it appears strange that phos- 

 phorescence should not be made useful in the same way, 

 and that while many of the lower plants exhibit this 

 phenomenon, yet in the flowering plants authentic 

 instances of phosphorescence under normal conditions 

 seem to be unknown. A priori we might consider that 

 phosphorescing flowers would be very efficient in attract- 

 ing night-flying insects for purposes of pollination, 

 especially as this method of arresting attention is shown 

 to be successful by several instances in the animal 

 kingdom. 



The portion of the book allotted to the movements of 

 plants in response to stimuli, is clearly written, and con- 

 tains accounts of much recent research in this field of 

 plant physiology. Illustrating this subject, there is 

 plenty of material for beautiful and striking experiments ;, 

 perhaps one of the prettiest, described by the author, is 

 an experiment on the chemotropism of the pollen-tube. 

 A leaf of Tradescantia is injected with a sugar solution, 

 and afterwards quickly washed in water and dried on 

 the surface. On the under surface, which is rich in 

 stomata, a number of pollen-grains are scattered, and the 

 leaf thus treated is kept in a damp chamber. After a 

 certain time it may be observed that the tubes of the 

 germinating pollen-grains are each directed towards 

 some one of the stomata, sho.wing that the sugar solution 

 in the stoma, and the intercellular spaces connected 

 therewith, induces a chemotropic movement in the 

 pollen-tube. 



In its new form the book is certainly one of the most 

 complete, if not the most complete, text-book of plant 

 physiology. For although it is much smaller than Sachs*' 



